The invention relates to an apparatus for the continuous cooking of wort used for the production of beer, consisting of a preheater heating the wort with the vapor from the cooking operation, a steam heater supplied with steam from an outside boiler, a reactor in which the heated wort is maintained for a period of time at constant elevated temperature and pressure, and at least one expansion evaporator.
It is already known to heat the hopped wort withdrawn by a pump from the mashing kettle at about 75.degree. C. to a temperature of about 95.degree. C. in a first heat exchanger, to about 115.degree. C. in a second heat exchanger, and lastly in a third to about 140.degree. C. Then the wort is passed through a reactor in the form of a cylindrical tank where it is kept at this last temperature for a certain length of time under a constant pressure of approximately 6 bar. The elevated pressure prevents the wort from boiling up too soon. Then follows a two-stage lowering of the pressure to about 1 bar absolute. The vapor that is released by this abrupt reduction of pressure is used for a regenerative heating of the wort from about 95.degree. to 115.degree. C. in a second heat exchanger. The wort is discharged from this evaporation tank at a temperature of about 120.degree. C. and, in a second evaporation tank connected to the outlet of the first evaporation tank, it is expanded from 1 bar of excess pressure to standard pressure corresponding to a wort temperature of approximately 100.degree. C.
The heat of the wort vapors from the second expansion stage is used to preheat the wort from 75.degree. C. to 95.degree. C. in a first heat exchanger. The third wort heating stage, also in the form of a heat exchanger, is designed for a final wort temperature of about 140.degree. C., and is supplied with direct steam of approximately 7 bar corresponding to 160.degree. C. (Brauwelt, Vol. 119,1979 No. 15, pp. 492-494). This high temperature cooking, continuous wort clarification and wort cooling permits the achievement of an immediate hot separation of sediment and rapid cooling to the pitching temperature.
The coefficient of evaporation is selected between 5 and 6%, and the concentration of the last run of wort and of part of the second wort is omitted. The temperature produced during the reaction period, which is now increased to 140.degree. C., considerably higher than the 100.degree. C. boiling temperatures formerly used in brewing kettles, for a shorter period of time, is necessary in order to achieve an evaporation of at least 7%.
The invention is aimed at considerably reducing the energy requirement and hops consumption in a continuous wort cooking operation of the above-described kind, and at achieving a substantial outgassing of the wort combined with an improvement of quality.